Extraction and recovery of copper from its ores



I Patented Sept. 1,1925.

UNITED STATES: PATENT OFFICE.

PHILLIP WILLIAM NEVILL; oFyEAs'r PERTH, WESTERN AUSTRALIA, AUSTRALIA, AS-

SIGNOR TO THE AUSTRALIAN MINERALS RECOVERY ooMPANYLIMI'rEn, or PERTH, WESTERN AUSTRALIA, AUSTRALIA. v I

EXTRACTION AND RECOVERY OF COPPER FROM ITS ORTZIS.

No Drawing.

To all whom it may concern:

Be it known that I, PII-InLIr \VILLIA 'NEVILL, of East Perth, in the State-of Vestern Australia, Commonwealth of Australia, have, invented an Improvement in the Ex traction and Recovery of Copper from Its Ores, of which the following description tralian Letters Patent N 0. 19,100, dated the 13th December, 1920.

In the metallic contact process above referred to, a naturally or artifically oxidized copper ore in the form of a pulpis acted on I by a metallic iron in the presence of a salt or salts whereby cement copper is liberated.

The cement copper can then be separated either by elutriation or. by the flotation process. It is obvious that by reason of the cement copper being in a relatively fine state of,division, there will be some danger of a film of oxide forming on the surface, which will preclude oiling and therefore yield a product not amenable to flotation separation,

In addition, it has been found that if the flotation process is carried out using air as the froth basis, soluble iron salts are large 1y destroyed (particularly ferrous salts) and so are not available for treating a fresh charge of ore.

It has been further found when conducting flotation using air that a certain proportion of the copper is frequently rendered soluble, presumably by the solvent action of ferric salts that are formed. The copper rendered soluble is of coursev irrecoverable by flotation.

The object of the present invention is to conduct the process of flotation sothat sur-' face oxidation of cement copper is inhibited, whilst excessivedestruction and oxidation of ferrous salts-is prevented.

. The invention consists broadl i in assin l P g a reducing gas or mixture of gases through and into the flotation circuit and also'if desired through the pachuca in which the cement copper is set free by the operation of the metallic contact process.

To enable the nature of the invention to a flotation machine.

' Application fi1edJanuary30, 1924. Serial No. 689,587.

be more readily understood, reference will now be made .to the accompanying examples. l

Eaaample N0. 1 (not according to this invent1on).-.500 grams of ore (150 mesh) and containing 8.1% of copper was formed into a pulp with 1500 czcs. of water, to which was added 50 gramseach of ferrous sulphate andcommon salt. and also 40 grams of sponge iron (60% F e.). After 10 minutes steam and air agitation in the pachuca, the mixture was agitated by air alonefor a further 10 minutes, prior to which was added 10 drops of eucalyptus oil. The mixture was then transferred to and treated in a flotation machine which yielded a concentrate containing 80% of the copper contents of'the ore. After treatment it was found that only 6 grams of soluble iron salts were left in the as'50 grams'were added. EwampZeNo. 2 (according to the invention).500 grams'of similarore to that solution, whereused imExample No. 1 was formed into a pulp with 1500 cos. of water,to which was added 15 grams \of ferrous sulphate and 1.5 grams of salt, an 42 grams of sponge iron (60% Fe). 'After steam and air agitation for 10 minutes, 10 drops of eucalyptus oil was. added and air agitation given for 10 minutes. The mixture was then diluted with 1000 c.cs. of 2% salt solution and transferred to and treated in During flotation coal gas was passed into the machine, so that such gas became the basis of the froth. A recovery of 83.8% of the. copper was obtained, and the residual solution con-' tained 3 grams of ferrous sulphate, so that there was a much smaller consumption than 'in Example No 1.

Example N0. 3 (according to the invent1on).500.grams of ore similar to that. used in previous examples was formed into a pulp with 2500 cars. of water, 50 grams each of ferrous sulphateand salt added, and also 40 grams of iron (60% Fe). After steam and air agitation for 10 minutes, 8 drops of eucalyptus oil was added and air agitation continued for 10 minutes. The product was transferred to and treated win a flotation machine at a temperature of 4L0" 0., 5 drops more oil being added. The

5 ual solution contained 43' grams of ferrous sulphate.

It will be obvious that the invention is not limited to the use of coal gas as thefroth basis, but that other reducing or similar functioning gases may be employed.

Theoretically a perfectly neutral gas should I be useful, but in practice it is necessary to have a gas in which there is sufficient of a reducing constituent to neutralize the oxidizing influ enize'of gases that are also almost invariably present.

I claim A'process for the recovery of copper cement comprising forming a copper ore pulp containing ferrous salt and subjecting the pulp to'flotation separation in the presence of reducing gas. sa1d gas not only prevenl1- ing oxidationof the copper cement but also preventing conversion of the ferrous salts into ferric salts.

Dated this 17th day of December, 1923.

' PHILLIP WILLIAM NEVILL. 

